In the Part 1 and Part 2 we had built the project, added the references, and generated keys. So in this post, we are going to add some basic codes and attributes into the project.
Firstly let's put our focus on MyControlFlowTask project.
In the MyControlFlowTask project, we need to add a using statement for the Microsoft.SqlServer.Dts.Runtime reference we created before, then make the MyControlFlowTask derived from the Task class.
Starts from here, we can add three override methods: InitializeTask, Validate, and Execute.
For these three methods:
- The InitializeTask will be called when we create the task on the IDE;
- The Validate method obviously will be called when we need to validate the task, such as setting of the task and validation phase before the excution phase;
- The Execute method will be called when we start to run the task;
So my screen looks like below. Because my purpose for this topic is to build a template, so for demostration purpose, I just want this task to pop up a message box and let me know, I am running successfully :P.
Now time to decorate this project a bit. Look at below screenshot, most attributes are easy to understand:
- DisplayName: it will be displayed on the IDE as the task name;
- Description: it will be displayed on the IDE when you move your mouse onto the task;
- UITypeName: This value will be used to build the relationship between the task and task UI. Note the type name must be in its full name;
- IconResource: the icon will be displayed on the IDE. However to build the icon, you need to select the icon, go to properties panel, change the Build Action to "Embedded Resource"
Now we have finished the task project. Time to work on the MyControlFlowTask_UI project. Firstly go to the MyControlFlowTask_UI class. This class will be acting as a bridge to connect the Task and our task form (To make it clear, MyControlFlowTask - MyControlFlowTaskUI - MyControlFlowTask_Form).
To work on it, we need to implement IDtsTaskUI interface:
When you implement the interface, there should be three methods added into the class: Delete, Initialize, and New. To make our template simple, we only need to ensure the property "TaskHostValue" can have an assigned value in the Initialize method.
Now time to link the UI to the form, we call the GetView method and pass the TaskHostValue property into the form. Notice the red line under the form, it is becasue we have not create this form.
Now add a Winform control into the MyControlFlowTask_UI project and name it "MyControlFlowTask_Form"
By default Visual Studio should have built the default constructor for us. But look back the step above, we need to have a constructor to receive the TaskHost value, so we need to create a different constructor:
We are close to the end. Now let's build the solution. (You may ask, what do you do to the form? Just a constructor? My answer is yes, just a constructor. Remember we are building a template. This form will serve the purpose of the task configuration, so at least in this post, as long as it can receive the TaskHost value, it is good enough)
If you follow the steps carefully, the compiled dll should be created under the ..\DTS\Tasks\ folder directly, and the assemblies should be registered in GAC as well.
Now open the SSDT or Visual Studio with BI developer, and create a package. You should see the task under the Common task category (note if you have SSDT opened already, you need to close it an dopen it again, because assemblies will be loaded at the beginning of the application.)
Drag the task onto the control flow design panel, double click it, the form should pop up.
Once click the OK button, the green tick icon should be shown on our first control flow task
Congradulations! We have create our first control flow task, and most importantly, this solution can be reused when we need to create a new control flow task, simply need to generate a new key.
So it is close to the end. But I planned to have a part 4, to discuss some extra things you may need to use when you need to create a business-ready task. Now see you next time.
